1. Field of the Invention
The present invention relates to a multilayer ceramic electronic component. In particular, the present invention relates to a multilayer ceramic electronic component that includes external electrodes including plated films provided on the surfaces of a ceramic body.
2. Description of the Related Art
Electronic equipment such as mobile phones, notebook computers, digital cameras, and digital audio equipment is becoming more and more compact. A large number of multilayer ceramic electronic components that enable the size of such an electronic device to be reduced and the performance thereof to be improved are used therein.
A typical multilayer ceramic electronic component includes a ceramic body that includes a plurality of ceramic layers formed on one another, internal electrodes formed inside the ceramic body, and an external electrode formed on a surface of the ceramic body. A multilayer ceramic electronic component is disposed on a conductive land of a mount board and is then mounted onto the board by a conductive bonding material, such as solder.
There is a growing demand for a multilayer ceramic electronic component having a reduced size.
However, in general, the characteristics of a multilayer ceramic electronic component tend to deteriorate when the size of the multilayer ceramic electronic component is reduced because an effective area in which internal electrodes overlap one another is reduced.
In a multi-terminal multilayer ceramic electronic component, it is necessary to form a plurality of external electrodes at a fine pitch. Paste-applying precision in a conventional thick-film paste firing method is limited. Therefore, it is difficult to form external electrodes with high precision when the conventional method is used.
To overcome the above difficulty, a method of forming external electrodes by plating has been proposed. With this method, it is possible to form a thin flat external electrode, which enables an increase in the effective area of the internal electrodes. In addition, since metal is deposited at the exposed edges of internal electrodes, it is possible to form external electrodes with high precision even when a fine pitch is required.
The use of dummy conductors (anchor tabs), for the purpose of improving the reliability of the growth of a plated film when external electrodes are formed directly by plating, that do not substantially contribute to the electric characteristics is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2004-327983. According to Japanese Unexamined Patent Application Publication No. 2004-327983, if the technique disclosed therein is used, it is possible to deposit metal not only at the exposed edges of internal electrodes but also at the exposed edges of dummy conductors. According to the Japanese Unexamined Patent Application Publication No. 2004-327983, this makes it possible to grow a plated film with increased reliability.
However, even when the method disclosed in the Japanese Unexamined Patent Application Publication No. 2004-327983 is used, a problem of insufficient growth sometimes occurs when attempting to form a plated film by applying electrolytic plating to an electronic component having a small size of, for example, 1608 (approx. 1.6×0.8×0.8 mm) or less. Specifically, with electrolytic plating, a current is applied when a medium, such as a steel ball, is brought into contact with the exposed portions of internal electrodes and dummy conductors. As a result, metal is deposited at the exposed portions. However, as the size of the electronic component is reduced, the area of an exposed portion is reduced. Therefore, the probability of successful contact of the medium and the exposed portion is reduced.